Self-locking core



Sept. 22, 1964 R. c. HATHORN 3,149,393

SELF-LOCKING CORE Filed June 30, 1961 2 Sheets-Sheet 1 Q 27' 22 ....mm 23 ;r III 5 INVENTOR. Fla 5 C. Haf/iorn.

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p 22, 1964 R. c. HATHORN 3,149,393

SELF-LOCKING coma Filed June 30, 1961 2 Sheets-Sheet 2 IN V EN TOR.

. Ray C. Hfhorm 1'9 1 BY M,QMRW

Hffo W'Le gs United States Patent 3,149,393 SELF-LOCKING CGRE Roy C. Hathorn, 1369 Kilby Terrace, Anniston, Ala. Filed June 31), 1961, Ser. No. 121,063 3 Claims. (Cl. -128) This invention relates to a self-locking core and more particularly to a core for a generally cylindrical end portion of a mold, such as molds for making pipe.

An object of my invention is to provide a self-locking core which shall be adapted for making either the bell or spigot end of a pipe in a centrifugal casting mold.

Another object of my invention is to provide a selflocking core which shall be accurately and positively set in position with a minimum of effort due to the fact that the rotation of the mold itself causes the core to move to proper seating relation relative to the mold.

Another object of my invention is to provide a selflocking core of the character designated which requires the insertion of a single member, thereby eliminating the necessity of inserting a plurality of pins, shims and the like and materially speeding up the positioning of the cores in the mold.

Another object of my invention is to provide a self locking core of the character designated which shall have a beveled surface thereon disposed to engage a corresponding beveled surface on the inner surface of molds whereby the strength of the core is greatly increased and the necessity of providing a back-up plate is eliminated.

A further object of my invention is to provide a selflocking core of the character designated which shall be in continuous contact with the adjacent surface of the mold and in which even pressure is applied to the core to hold the same in place.

A still further object of my invention is to provide a self-locking core of the character designated which shall be simple of construction, economical of manufacture and one which may be employed on conventional type molds with a minimum change in the mold itself.

Heretofore in the art to which my invention relates, it has been the usual practice to secure the end core members in the mold for casting pipe by placing the core members in place and then driving pins through the mold whereby they contact and grip the core members. In order to assure a firm contact between the pins and the core member, shims and the like have been employed. This assembly of the core members not only requires considerable time and effort, but necessitates the provision of a plurality of parts which must be assembled separately and disassembled separately. Also, the use of separate pin and shims and the like for securing the core in place oftentimes results in a core being set improperly due to the fact that even pressure is not applied to all portions of the core member.

To overcome the above and other difiiculties, I provide a core member which only requires the insertion of a single member into the end of the mold whereby rotation of the mold itself moves the core into proper position and in locked relationship to the mold. A plurality of cam surfaces are provided at angularly spaced intervals around the core in position to engage stationary detents carried by the mold whereby upon relative rotation between the core and the mold, the core moves automatically into locked position.

Core members embodying features of my invention are illustrated in the accompanying drawings, forming a part of this application, in which:

FIG. 1 is a side elevational view, partly broken away and in section, showing core members for forming the bell and spigot ends of a pipe;

FIG. 2 is an end elevational view taken generally along the line 22 of FIG. 1;

3,149,393 Patented Sept. 22, 1964 FIG. 3 is an end elevational view taken generally along the line 33 of FIG. 1;

FIG. 4 is a sectional view taken generally along the line 44 of FIG. 2 showing the core member rotated relative to the mold whereby it is in locked position;

FIG. 5 is a sectional view taken generally along the line 55 of FIG. 3, the mold being omitted for the sake of clarity;

FIG. 6 is an elevational view showing a modified form of my invention in which an annular member having cam surfaces thereon is adapted for use with a conventional type core member;

PEG. 7 is an enlarged view taken generally along the line 77 of FIG. 6; and,

PEG. 8 is an enlarged, fragmental view showing the annular member of FIGS. 6 and 7 locked in place within a flask.

Referring now to the drawings for a better understanding of my invention, I show a mold indicated generally at 113 having a spigot end 11 for casting the spigot end of a pipe and a bell end 12 for casting the bell end of a pipe. The spigot end 11 of the mold is provided with an inwardly tapered or beveled surface 13 which is connected at its outer portion to an enlarged diameter portion 14. The portion of the spigot end 11 outwardly of the enlarged diameter portion 14 flares outwardly as at 16.

The core member for the spigot end of the mold comprises an annular body portion 17 having an inwardly tapered or beveled portion 13 which is provided with an outer beveled surface which also tapers inwardly and corresponds generally to the adjacent surface 13 of the spigot end 11 when the core is in place, as shown in FIG. 1. Formed integrally with the outer portion of the beveled portion 18 of the annular member 17 is an outwardly projecting annular flange 19 and formed integrally with the inner portion of the beveled member 18 is an inwardly extending annular flange 21.

As shown in FIG. 1, the annular flange 19 extends in a radial direction relative to the mold when inserted therein. Angularly spaced recesses 22 are provided in the periphery of the radially extending flange 19, as shown in FIG. 2, for receiving inwardly projecting detents or pins 23 carried by the end of the spigot portion 11. The outer portions of the pins 23 extend within and are secured within suitable openings 24 whereby the pins form a stationary part of the spigot end 11 and rotate therewith.

Cam surfaces 26 are formed on the outer face of the radially extending flange 19 in position to engage the inner portion of the pins 23, as shown in FIG. 4, after the core member is inserted past the pins 23 and then rotated. Preferably, a cam surface 26 extends between adjacent recesses 22, as shown in FIG. 2. Each cam surface 26 is formed by providing a lower portion for the cam as as 27 and a raised portion as at 28. The lower portion 27 of the cam is so positioned relative to the raised portion 28 thereof that the lower portion 27 leads the raised portion when the core member is rotated in a clockwise direction, as viewed in FIG. 2. Upon inserting the core member and then rotating the same in a clockwise direction, the cam surface 26 engages the adjacent pins 23 whereby the pins continuously ride toward the raised portions 28 thereof, thereby locking or wedging the core member firmly in the place. In actual practice, I find that the rotation of the mold itself, where the mold is employed for centrifugally casting pipe, rotates the core member the proper angular distance relative to the pins 23 whereby the core member is locked in place.

The core member for the bell end of the mold 10 comprises a body portion 29 which is-annu1ar in shape and is provided with an outwardly projecting radial flange 19* at the outer end thereof and an inwardly projecting flange 21* at the inner end thereof. The annular flange 19 is adapted to fit within an enlarged diameter portion 14 of the bell end of the mold, as shown in FIG. 1. The bell end of the mold is provided with an inwardly tapered or beveled surface 13 and the portion of the bell end outwardly of the enlarged diameter portion 14 flares outwardly as at 16*. The bell end of the mold may also be provided with inwardly tapered or beveled surfaces 31 and 32, as shown. Formed integrally with the radially extending flange 19 is an inwardly tapered or beveled portion 18 having an outer surface which is tapered inwardly corresponding to the taper of the beveled surface 13* of the mold.

The outwardly projecting radial flange 19 is provided with angularly spaced recesses 22 therein for passing inwardly projecting detents or pins 23 carried by the ends of the bell end 12. The pins 23* are secured in place within suitable openings 24 whereby the pins form a stationary part of the mold and rotate therewith.

Cam surfaces 26 are provided on the outer face of the radially extending flange 19" between adjacent recesses 22*- in position to engage the inner surface of the pins 23 upon inserting the body portion 29 and rotating the same in a counterclockwise direction relative to the mold, as viewed in FIG. 3. The cam surfaces 26 are provided with lower portions 27 and raised portions 28 with the lower portions 27 leading the raised portions 28 when the flange 19 is rotated in a counterclockwise direction, as viewed in FIG. 3.

From the foregoing description, the operation of my improved self-locking core will be readily understood. The core member is inserted in either the bell end or spigot end of the mold by aligning the openings 22 and 22 with the pins 23 or 23, as the case may be, whereby the recesses receive the pins and permit insertion of the flange 19 or 19 past the pins. After the radially extending flange 19 or 19 has passed the pins 22 or 22*, the core is rotated whereby the pins 23 or 23 engage the cam surfaces 26 or 26 and ride toward the raised portions thereof, thereby forcing the core member firmly into seated position relative to the molds. Where the core member is inserted in a mold for centrifugally casting pipe or the like, the rotation of the mold itself brings about the required relative angular movement of the core member and the mold whereby the pins and the ad- 4 ing inwardly projecting detents or pins 23' carried by the bell end 12 of the mold. The pins 23 are secured in place within suitable openings 24 whereby the pins form a stationary part of the mold and rotate therewith as described hereinabove.

Arcuate cam members 25 are carried by the outer surface of the annular member 34 between adjacent recesses 22 in position to engage the inner surface of the pins 23 upon inserting the core and the annular member 34 and rotating the same in a counterclockwise direction relative to the mold, as viewed in FIG. 6 Each cam member 25 is provided with a cam surface 26 which in turn has a lower portion 27 and a raised porjacent cam surfaces move relative to each other to lock 7 the core member in place. The inwardly tapered or beveled surfaces 13 or 13 firmly engage the adjacent inwardly tapered surfaces on the beveled portions 18 or 18 whereby continuous contact is provided between the core member and the mold and the strength of the core ameter portion 14 of the bell end of the mold, as shown in FIG. 8. The bell end of the mold is provided with an inwardly tapered or beveled surface 13 and the portion of the bell outwardly of the enlarged diameter portion 14 flares outwardly as at 16 The bell end of the mold 10 may also be provided with inwardly tapered surfaces 32 as shown. Formed integrally with the radially extending flange 19 is an inwardly tapered or beveled portion 18 having an outer surface which is tapered inwardly corresponding to the taper of the beveled surface 13 of the mold. a

As shown in FIG. 6, the annular member 34 is provided with angularly spaced recesses 22 therein for passtion 28 with the lower portion 27 leading the raised portion 28 when the annular member 34 is rotated in a counterclockwise direction, as viewed in FIG. 6.

To facilitate insertion and removal of the annular member 34, I provide the annular member 34 with outwardly projecting handle members in the form of pins 36.

From the foregoing description, the operation of my improved apparatus shown in FIGS. 6, 7 and 8 will be readily understood. The annular member 34 is positioned adjacent the outer surface of the radially extending flange 19 and the entire core unit is inserted in the bell end or spigot end of the mold, as the case may be, by aligning the recesses 22 with the pins 23 whereby the recesses 22 receive the pins and permit insertion of the annular member 34 past the pins. That is to say the annular member 34 may be employed with a bell end 12 of the mold 10 or may be employed with a spigot end of the mold, as described hereinabove. After the annular member 34 has passed the pins 23, it is rotated whereby the pins 23 engage the cam surfaces 26 and ride toward the raised portions 28 thereof, thereby forcing the core member firmly into seated position relative to the mold. Also, where the annular member 34 is employed for centrifugally casting pipe or the like, the rotation of the mold brings about the required relative angular movement of the annular member and the pins whereby the pins and the adjacent cam surfaces move relative to each other to lock the annular member 34 and the core in place.

From the foregoing, it will be seen that I have devised an improved self-locking core member which may be inserted into a mold with a minimum of effort and without the necessity of having to secure the core member in place by removable pins, shims and the like. By providing cam surfaces on the outer face of the core member which are adpted to engage stationary members carried by the mold, the core member is firmly locked in place by merely rotating the core member and the mold relative to each other. Also, by providing beveled contact surfaces between the core member and the molds, the strength of the core member is greatly improved and there is no necessity of providing a back-up plate. Furthermore, by providing cam surfaces at angularly spaced intervals around the core member which engage angularly spaced members carried by the mold, even and constant pressure is exerted against the core member at all times, thus assuring proper seating of the core member.

While I have shown my invention in several forms, it will be obvious. to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a self-locking composite core for a generally cylindrical end portion of a' mold having a reduced diameter portion axially inward of the end thereof:

(a) an annular rigid body member disposed to fit within said end portion of the mold with a portion of said body member bearing against said reduced diameter portion to limit inward movement of said body member axially of said mold,

(b) an annular, enlarged diameter portion formed integrally with the outer end of said body member,

(c) detents mounted adjacent the end of said mold and projecting radially inward thereof alongside the outer surface of said enlarged diameter portion while said body member is against said reduced diameter portion,

(d) there being recesses in the periphery of said enlarged diameter portion in position to receive said detents upon movement of said enlarged diameter portion axially inward of said mold past said detents, and

(e) cam surfaces formed integrally with the outer surface of said enlarged diameter portion between adjacent recesses in said enlarged diameter portion with the lower portion of each cam leading the raised portion thereof upon relative angular movement of said enlarged diameter portion and the detents in one direction and being in position to engage the inner sides of said detents upon relative angular movement of said enlarged diameter portion and said detents in said one direction after insertion of said enlarged diameter portion inwardly of said detents. 2. In a self-locking composite core as defined in claim 1 in which there are a plurality of angularly spaced recesses in the periphery of the annular enlarged diameter portion in position to receive angularly spaced, inwardly and radially extending detents carried by the mold.

3. In a self-locking composite core as defined in claim 1 in which the detents are in the form of inwardly and radially extending pins, there being openings through the mold adjacent the end thereof for receiving said pins.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A SELF-LOCKING COMPOSITE CORE FOR A GENERALLY CYLINDRICAL END PORTION OF A MOLD HAVING A REDUCED DIAMETER PORTION AXIALLY INWARD OF THE END THEREOF: (A) AN ANNULAR RIGID BODY MEMBER DISPOSED TO FIT WITHIN SAID END PORTION OF THE MOLD WITH A PORTION OF SAID BODY MEMBER BEARING AGAINST SAID REDUCED DIAMETER PORTION TO LIMIT INWARD MOVEMENT OF SAID BODY MEMBER AXIALLY OF SAID MOLD, (B) AN ANNULAR, ENLARGED DIAMETER PORTION FORMED INTEGRALLY WITH THE OUTER END OF SAID BODY MEMBER, (C) DETENTS MOUNTED ADJACENT THE END OF SAID MOLD AND PROJECTING RADIALLY INWARD THEREOF ALONGSIDE THE OUTER SURFACE OF SAID ENLARGED DIAMETER PORTION WHILE SAID BODY MEMBER IS AGAINST SAID REDUCED DIAMETER PORTION, (D) THERE BEING RECESSES IN THE PERIPHERY OF SAID ENLARGED DIAMETER PORTION IN POSITION TO RECEIVE SAID DETENTS UPON MOVEMENT OF SAID ENLARGED DIAMETER PORTION AXIALLY INWARD OF SAID MOLD PAST SAID DETENTS, AND (E) CAM SURFACES FORMED INTEGRALLY WITH THE OUTER SURFACE OF SAID ENLARGED DIAMETER PORTION BETWEEN ADJACENT RECESSES IN SAID ENLARGED DIAMETER PORTION WITH THE LOWER PORTION OF EACH CAM LEADING THE RAISED PORTION THEREOF UPON RELATIVE ANGULAR MOVEMENT OF SAID ENLARGED DIAMETER PORTION AND THE DETENTS IN ONE DIRECTION AND BEING IN POSITION TO ENGAGE THE INNER SIDES OF SAID DETENTS UPON RELATIVE ANGULAR MOVEMENT OF SAID ENLARGED DIAMETER PORTION AND SAID DETENTS IN SAID ONE DIRECTION AFTER INSERTION OF SAID ENLARGED DIAMETER PORTION INWARDLY OF SAID DETENTS. 